(CBSNews) BALTIMORE -- A Baltimore judge found Officer Caesar Goodson, who drove the police van where Freddie Gray's neck was broken, not guilty of "depraved-heart" murder on Thursday.

Circuit Judge Barry Williams also acquitted Goodson of manslaughter, assault, reckless endangerment and misconduct in office in the bench trial.

Twenty-five-year-old Gray died a week after suffering a spinal injury in Goodson's wagon last year, where officers left him handcuffed and shackled but unrestrained by a seat belt. His death set off protests and violence, and prompted State's Attorney Marilyn Mosby to bring charges against six officers.

The sweeping case ended the career of the police commissioner and aborted the political future of the mayor.

In December, Officer William Porter walked free after a hung jury. Last month in another bench trial, Williams found Officer Edward Nero not guilty. Both officers faced lesser charges than Goodson.

At the start of Goodson's trial earlier this month, Williams scolded prosecutors for failing to turn evidence over to the defense about another prisoner in the transport van with Gray.

Mosby's allegations that six officers intended to fatally injure the resistant prisoner prompted five of them to sue her for defamation. Her chief deputy, accused of withholding evidence, told the judge that the lead police investigator had pressured the coroner to falsely declare Gray's death an accident.

"It is extraordinarily rare to hear a prosecutor accuse a reputable, prominent lead detective of sabotaging the state's case," said Warren Alperstein, a prominent attorney in the city. "Calling into question a detective who the commanders appointed to lead the case sends a clear message. It breeds distrust."

Fissures had formed even before Mosby vowed last year to deliver justice to an outraged citizenry. She said the charges resulted from a "comprehensive, thorough and independent investigation," even though police investigators said they had felt pressured to hand over their evidence prematurely.

"I don't know anything about this case," the investigator in question, Dawnyell Taylor, told the Baltimore Sun shortly after the officers were charged.

Mosby and everyone else involved in the trials are prohibited by the judge from commenting.

Since Gray's death in April 2015, Baltimore police have been under a microscope.

The U.S. Justice Department has been investigating allegations of widespread abuse and unwarranted arrests. The mayor fired her police commissioner Anthony Batts and promoted his deputy, Kevin Davis, but decided against a re-election bid amid criticism of her handling of the riots.

And Maryland's legislature updated the Law Enforcement Officers' Bill Of Rights, in the law's first significant overhaul since it was established 1974.

Still, many feel the changes didn't go far enough. Police supervisors must still wait 5 days before questioning officers suspected of committing crimes; it used to be 10. And officers still can't be fired without an internal review or a felony conviction, even if, like Goodson, they refuse to talk with investigators.

Mosby's office has made other decisions that frustrate police: In March, prosecutors dropped charges against nine people charged after a sweeping raid found drugs, guns and ammunition; two suspects were soon charged in new crimes, including a quintuple shooting on Memorial Day.

Davis responded carefully, saying that while police and prosecutors have a "working" and "healthy" relationship, more must be done.

"There's a hyper focus on the police: What are the police doing, what's the plan, what's the strategy. We have those strategies and we're making progress," he said. "There are other pieces to that law enforcement puzzle I believe need to be held to that same standard."

Baltimore attorney Steve Levin praised police for their reforms in the past year.

"The police are now wearing cameras on their uniforms, and even have cameras in their police vans," he said. "But I think it'll soon be time to talk about reform in the prosecutor's office. As the judge himself said, if the most senior attorneys in the office don't recognize exculpatory material, that's a problem."